Geoege evans



(No Model.)

G. EVANS. MANUFACTURE OF ARTIFICIAL TOOTH GROWNS. No. 378,347.

Patented Nov. 15, 1887.

ZNVENTOR Mm WITNESSES: 7

BY 7 h @1144 Y ATTORNEY UNITED STATES PATENT OFFICE.

GEORGE EVANS, OF NEl/V YORK, N. Y.

MANUFACTURE OF ARTIFICIAL TOOTH-CROWNS.

fiPECIFICATION forming part of Letters Patent No. 373,347, dated November 15,1887.

Application filed December 27, 1886. Serial No. 222,634. (No model.)

To all whom it may concern:

Be it known that 1, GEORGE EVANS, a citizen of the United States, residing at the city,

county,and State of New York, haveinvented certain new and useful'lmprovements in the Manufacture of Artificial Tooth-Crowns, of which thefollowing isa specification, reference being made to the accompanying drawings, forming apart of the same.

This invention relates to artificial metallic crowns made from a blank of metal into a form corresponding to that of a natural tooth to be covered or substituted; and in order that others skilled in the art to which my invention appertains may understand and use the same I will proceed to describe its construction, explain its operation, and set forth in the appended claims its novel characteristics.

Referring to the drawings, Figure 1 represents a section of a metallic crown-blank of a single piece; Fig. 2, an exterior view of the same composed of two pieces; Fig. 3, an exterior view of a contoured molar-tooth crown made by the improved method herein described; Fig. 4, a side viewof asectional mandrel; Fig. 5, an end view of the same; Fig. 6, an end view of a separate mandrel; Fig. 7, a perspective view of .a partially-disconnected mandrel; and Fig. 8, a perspective view of a mandrel, crown, and crown-shapingdevice.

The present invention has for its object to produce an artificial crown contoured so as to present a grinding-surface and sides corresponding precisely with those which individually characterize an original tooth-a result which corresponds to that which I have described in an application filed December 9, 1886, No. 221,086, but which is obtained by a different means, as herein set forth.

From the tooth to be crowned an accurate impression is taken by applying to its surface a plastic materialsuch, for instance, as plaster-of-parisand afterward dividing the same, so asto remove it in parts from the tooth without disturbing the impression therein corresponding to the irregularities of said tooth. This mold being now placed together and allowed to harden is used as a cavity in which to cast amandrel of easily-fusible alloy, or other material of suitable stability when hardened. The mandrel thus produced is now divided into several convenient parts or secdetached in Fig. 7; or they may be thus separately cast by interposing suitable partitions in the mold preparatory to casting.

The sections a are held in proper relation when assembled together by means of a suitable clamping device, or by the hand applied to their extended portions or shanks b. the cup-shaped cap or blank 0, Fig. l, of platinum, gold, or other suitable thin malleable metal, or component parts 0 c of a similar blank, Fig. 2, to be soldered into one piece, are now introduced the crown ends of the several sections composing the sectional mandrel, preferably the exterior sections first and the central one having parallel or wedging sides last, the exterior of said mandrel being thus expanded into the blank; or should the tooth be narrow, as in the instance of a bicuspid tooth, the mandrel may be forced into the'blank after being assembled, or the mandrel may be made solid. The crown is now formed by exterior application of a suitable burnishing tool working the metal into the recesses and irregularities peculiar to the surface of the mandrel, whereby a contoured shape-such as represented by Fig. 3-is produced. The sectional mandrel is after completion of the blank dropped out in pieces, the central piece or pieces being removed first,which is obviously necessary, in order to avoid disturbance of the contoured sides of the crown which converge variously toward its reduced aperture. The crown-shaping device, Fig. 8, consists of. a sleeve, (Z, of metal, which, being bellmouth shaped at its lower end, will, when placed over the mandrel-shank b and forced toward the blank 0, contract the aperture of the same against the diverging sides of the mandrel from the shape shown by dotted lines approximately into the contoured shape, fa-

cilitating thereby the subsequent operation of burnishing.

I claim as my invention- 1. Asectional mandrel for forming a hollow metallic tooth-crown, said mandrel having a contour corresponding to that of an original tooth to be fitted or replaced and composed of separable sections so divided as to permit the Into removal ofthe same subsequent to the forming pressing the open end of said metallic toothprocess herein described. crowns, substantially as described, upon said 2. In a device for forming metallic toothmandrel. crowns, the combination, with a sectional man- GEORGE EVANS. 5 drel having diverging acting surfaces, as I Witnesses:

shown, of a compressing-sleeve having corre- CHAS. V. FORBES,

AUGUSTUS OREVELING.

sponding converging acting surfaces for com- 

